DTL is riskier with a higher net, shorter length court, and a sideline so close. But if your opponent hits hard DTL, you may not want to try to change direction on the ball and risk an error, so then you just hit back up the line, but now you have more court to cover too as you need to start to shade over to the crosscourt side.

I am not sure the Spanish advocate rallying DTL. It seems they go crosscourt or to the middle of the court with lots of topspin from the clay court matches I have seen.

I would say both advocate crosscourt.. but since spanish players use lots of topspin and get plenty of net clearnece, DTL wouldn't really hurt them as long as they don't hit the ball long.. If you go DTL from the duece side and have lots of topspin, the ball will bounce high on your opponents backhand and cause them to play a defensive stroke.

Never heard of that. Tennis has alays been based on high percentage play, especially in the pros. With pros being so good and so fast, taking chances on low percentages shots as a rally shot is foolish.

If the down the line shot is so important to them, then they would be changing the direction of the ball a lot. Sometimes being pros they can change direction on a ball that would be deemed difficult for us but eay for them. However, they practice an awful lot and they have the strength and timing to pull shots we woould be taking a lot of risk on.

As far as centering their game around the down-the-line shot for rallies, I like Camilio would ask for proof. I doubt it, or at least you misunderstood it.

Agree w/ above few post re percentage shots; however, w/ western forehand, I think the preferred grip of most of the Spaniards, the inside out forehand shot lends itself well to DTL. So maybe the half-truth is partly the grip?

No, sorry thats just not true.
Here in Spain we work as much on the crosscourt rally as down the line.
The crosscourt is drilled to open the court, and the down the line to finish the point, or use it in an attacking way.A down the line hit just for the sake of it at a good level will be punished with a cross court shot.
Just work on both as much as poss.